A conventional magnetic head supporting mechanism (suspension) in a magnetic disk storage comprises: a flexure member for supporting a slider loaded with a magnetic head; a load beam for holding the flexure member and applying a pressing load to the slider; and a spacer mount for connecting the load beam to a positioner mechanism.
In the case of the floating type magnetic head supporting mechanism, the slider generally undergoes an air viscous flow, created by high speed rotation of a magnetic disk (a recording medium), on an ABS (air bearing surface) provided on the side opposite to the magnetic disk to form an air layer which permits the slider to float over the magnetic disk while leaving a minute gap (floating height) of several tens of nm between the slider and the magnetic disk.
At that time, in order to stably maintain the floating height, it is necessary to suppress the slider supporting rigidity (roll/pitch rigidity) of the flexure member to ensure the flexibility of the floating motion.
On the other hand, high-speed and high-precision positioning of the magnetic head is indispensable for realizing high speed access to data in the magnetic disk storage, and high rigidity in a direction (seek direction) perpendicular to the longitudinal axis is required of an in-line type magnetic head supporting mechanism (in-line type: a magnetic head supporting mechanism wherein the load beam and the slider are provided so that the longitudinal axis of the slider is parallel to the longitudinal axis of the load beam) of a rotary actuator system (a positioner mechanism wherein the magnetic head is moved through arcuate motion of the magnetic head supporting mechanism by a voice coil motor).
Prior art techniques, wherein the load beam per se is improved in rigidity and strengthened to improve the vibration properties, include one wherein a rib is applied to the middle position of the load beam excluding a loading, bent section for applying a pressing load to the slider (Japanese Patent Laid-Open No. 28801/1994), one wherein ribs are applied to the loading, bent section (Japanese Patent Laid-Open No. 222472/1987), and one wherein a flange section is provided also on both the right and left sides of the loading, bent section (Japanese Patent Laid-Open No. 222472/1987).
An example of the conventional in-line type magnetic head supporting mechanism comprises a load beam, a flexure member, a slider, a spacer mount, a flange, a loading, bent section, a magnetic head, and a pivot.
The spacer mount is connected to a positioner mechanism to carry out positioning on a required track of a magnetic disk. The loading, bent section in the load beam has been plastically deformed and is constructed so that, when the slider is incorporated into the magnetic disk (recording medium D), a predetermined pressing load is applied to the slider.
The slider floats over the magnetic disk (recording medium) at a position where a balance between the pressing load and the buoyancy created by the air viscous flow on the ABS is offered. For the flexure member in the above magnetic head supporting mechanism, there are two structures, that is, a pivot structure wherein a slider bearing member has a predetermined pivot which supports a slider at a point and a pivotless structure wherein a flexure member and a load beam are integrally molded to eliminate the need to provide a pivot and to support a slider by the face.
The pivot structure, which has excellent slider bearing rigidity, has hitherto been mainly used. The advance of a reduction in size of the magnetic disk storage and an increase in access speed, however, has lead to a tendency that the flexure member having the pivotless structure, which is excellent in convenience for assembling the magnetic head supporting mechanism into between a plurality of magnetic disks, as well as in dynamic vibration properties during operation of the magnetic disk storage, is also extensively used.
Further, in consideration of mounting of an MR (magneto resistive) head capable of coping with high TPI (track per inch) and other matters, for example, a suspension integral with wiring has also been proposed which comprises a plurality of signal wires formed as a thin layer on the surface of a load beam. In the suspension integral with wiring, a flexure member and the load beam should be integral with each other for reasons of patterning. Therefore, the pivotless structure is adopted also in the suspension integral with wiring.
When an HGA (head gimbal assembly) is incorporated into a magnetic disk storage wherein a plurality of magnetic disks (recording media) are stacked on top of each other or one another, a mounting method has been used which comprises: applying a specialty magnetic head insertion jig (an assembly jig) to a magnetic head assembly comprising a plurality of magnetic head supporting mechanisms with the flexure being regulated by a predetermined clamp jig or the like; further flexing the load beam to release the clamp jig; transferring, in this state, the magnetic head onto magnetic disk; and removing the magnetic head insertion jig to release the flexure of the load beam and incorporating the slider loaded with a magnetic head onto the magnetic disk.
At the present time, however, a demand for improved mounting density of the magnetic disk per se and reduced size of the magnetic disk storage has lead to narrowed spacing between magnetic disks. This in turn results in unsatisfactory lift clearance of the load beam, making it difficult to incorporate the magnetic head onto the magnetic disk. For the above mounting of the magnetic head between the narrow space between the magnetic disks, a magnetic head insertion method is required which enables the magnetic head to be mounted onto the magnetic disk in the simplest possible manner in the smallest possible space.
The above conventional techniques, however, had the following drawbacks. Specifically, in the case of the magnetic head supporting mechanism loaded with a flexure member having a pivotless structure, the slider-pressing load is applied through the flexure member rather than through the pivot. Therefore, application of a large pressing load often creates a load loss (escape of load) due to the deformation of the flexure member per se. For this reason, a light pressing load design is required particularly of the magnet head supporting mechanism having a pivotless structure, with the flexure member and the load beam being provided integrally with each other, which is used in a suspension integral with wiring and the like.
More specifically, the conventional magnetic head supporting mechanism having a pivot structure is designed so that the pressing load is about 3.5 to 5.0 gf, whereas the suspension integral with wiring (pivotless structure) is currently designed so that the pressing load is about 0.5 to 1.0 gf. The above light load design for the magnetic head supporting mechanism is an important technique associated with a design for a reduction in size of the slider for increasing the recording density of the magnetic disk and a demand for a small floating height.
Specifically, although a reduced slider-pressing load creates an advantage of an improvement in magnetic disk floating properties, it also creates disadvantages such as lowered air layer rigidity and lowered acceleration of breakoff of the medium. More specifically, the lowered air layer rigidity leads to a deteriorated capability of the slider to follow up the movement of the magnetic disk, and the lowered acceleration of breakoff of the medium deteriorates the impact resistance at the time of stopping of the storhe.
At the present time, by virtue of the development of a negative pressure type slider, the problem involved in the lowered air layer rigidity is being solved. However, as expressed by the following equation (1), the medium breakoff acceleration is proportional to the pressing load of the slider, making it difficult to provide a light load design, for a highly impact-resistant magnetic head supporting mechanism, according to the conventional technique. EQU Acc=F/(M+m) 1)
wherein
Acc represents medium breakoff acceleration; PA1 F represents slider-pressing load; PA1 M represents equivalent mass of magnetic head supporting mechanism; and PA1 m represents mass of slider. PA1 the joining site, provided between the slider bearing member and the flexure member, having spring properties, the slider bearing member being inclined to the load beam. PA1 the joining site, provided between the slider bearing member and the flexure member, having spring properties, the slider bearing member being inclined to the load beam; and PA1 installing the magnetic head supporting mechanism between a plurality of magnetic disks in such a manner that the slider bearing member is pressed to suppress the inclination of the slider bearing member, permitting the slider bearing member to be on substantially the same plane as the load beam and, thereafter, the magnetic head supporting mechanism is inserted between the magnetic disks.
On the other hand, in order to realize a high recording density of not less than 10 Gb/in.sup.2 in a magnetic disk, contact type sliders, such as near contact sliders and contact sliders, has also been developed. In the near contact slider, the floating height of the slider is limited to the glide height level (about 20 nm) to improve data reading properties.
In the case of the near contact slider, however, as described above, the floating height is very small, while the floating of the slider is unsteady. This causes the slider to come into contact with the recording medium in the case of a certain track position of the magnetic disk and a certain yaw angle. For this reason, in order to prevent the breaking of the magnetic head by collision with or sliding on the recording medium or to prevent recorded data from becoming thermally unstable by contact friction, the near contact slider should be designed so that the pressing load is much lower than that in the conventional floating type magnetic head slider.
Also in the case of the contact slider wherein data are recorded or reproduced in such a manner that the magnetic head is always slid in contact with the magnetic disk (recording medium), an ultra-low load design (up to several tens of mgf) is required for reducing the abrasion loss without sacrificing stable contact follow-up of the magnetic head. In a magnetic head supporting mechanism loaded with the above contact slider (contact suspension), a lowering in medium breakoff acceleration due to a light load design significantly deteriorates the impact resistance of the magnetic disk storage.